PSLE
Eva bought some chocolate bars and gave half of it to Jeremy. Jeremy bought some jelly beans and gave half of it to Eva. Eva ate 2 jelly beans and Jeremy ate 32 chocolate bars. The ratio of Eva's jelly beans to chocolate bars became 1 : 5 and the ratio of Jeremy's jelly beans to chocolate bars became 1 : 2. How many chocolate bars did Eva buy?

	Eva		Jeremy
	Jelly beans	Chocolate bars	Jelly beans	Chocolate bars
Before	1 u + 2	5 u	1 p	2 p + 32
Change	- 2			- 32
After	1 u	5 u	1 p	2 p

After Eva gave half of the chocolate bars to Jeremy and Jeremy gave half of his jelly beans to Eva, Jeremy and Eva had same number of jelly beans and chocolate bars before each ate some.

5 u = 2 p + 32 
5 u - 32 = 2 p --- (1)

1 u + 2 = 1 p --- (2)

Make p the same.

(2)_x2
2 u + 4 = 2 p --- (3)

(1) = (3)
5 u - 32 = 2 u + 4 
5 u - 2 u = 4 + 32
3 u = 36

1 u = 36 ÷ 3 = 12

Number of chocolate bars that Eva bought
= 2 x 5 u
= 10 u
= 10 x 12
= 120

Answer(s): 120